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      <title>谈谈MySQL中项目架构中的作用 - 交互式测验</title>
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          <div class="quiz-container">
            <div class="quiz-header">
              <h1>谈谈MySQL中项目架构中的作用 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
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    "question": "根据文档，“引用完整性 (Referential Integrity)” 主要通过哪种机制来保证？",
    "options": [
      "通过主键约束确保每一行数据的唯一性。",
      "通过外键约束来保持关联表之间数据的一致性。",
      "通过字段类型和长度限制来确保数据的格式正确。",
      "通过触发器和存储过程来实施复杂的业务规则。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "引用完整性是通过外键约束来实现的。它确保了在一个表中作为外键的值，必须对应另一个表（父表）中存在的主键值，从而维护了表与表之间引用关系的一致性和有效性。",
    "source": "文档中「数据完整性（Integrity）」部分的「引用完整性」条目",
    "hint": "思考一下在数据库设计中，哪种约束是用来连接两个表并确保它们之间关系有效的。"
  },
  {
    "question": "文档在“数据持久化”部分提到，ACID特性对于保证数据操作的可靠性至关重要。数据库系统是如何利用事务日志来保障这一点的？",
    "options": [
      "通过将事务日志直接存储在内存中以加速读写操作。",
      "通过记录事务操作到日志中，以便在系统崩溃或故障时能够恢复数据。",
      "事务日志主要用于优化查询性能，而不是用于数据恢复。",
      "通过加密事务日志来防止数据被未授权访问。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档明确指出，数据库通过将事务操作记录到事务日志中，来确保数据的持久性和完整性。当系统发生崩溃等故障时，可以利用这份日志来回滚未完成的事务或重做已提交的事务，从而将数据恢复到一个一致的状态。",
    "source": "文档中「数据持久化」部分的「事务处理与ACID特性」条目",
    "hint": "当系统意外关机后重启，数据库是如何知道哪些操作完成了，哪些没有完成的？"
  },
  {
    "question": "在“性能优化”一章中，哪项策略被归类为“数据库设计优化”以应对大型数据表？",
    "options": [
      "使用Redis等工具缓存常用查询结果。",
      "通过负载均衡器分散请求负载。",
      "对大型数据表进行分区或分表。",
      "升级服务器的CPU和内存硬件。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "文档在“数据库设计优化”小节中明确提到了“分区和分表”是一种针对大型数据表的优化策略。这种方法可以将一个大表的数据物理上或逻辑上分散到多个部分，从而减少单一节点的负载，提升查询性能和并发处理能力。而缓存、负载均衡和硬件升级在文档中被归类于其他优化类别。",
    "source": "文档中「性能优化」部分的「1. 数据库设计优化」小节",
    "hint": "当一张表变得非常巨大时，从设计的角度出发，你会如何将其“拆分”来提高效率？"
  },
  {
    "question": "文档描述了三种不同的数据备份类型。其中，“差异备份 (Differential Backup)” 的正确定义是什么？",
    "options": [
      "只备份自上一次任何类型（完全或增量）备份以来发生变化的数据。",
      "复制整个数据库的所有数据和对象。",
      "备份自上一次“完全备份”之后所有发生变化的数据。",
      "仅备份数据库的事务日志文件。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "根据文档定义，差异备份是备份自上次“完全备份”后发生变化的数据。这与增量备份（备份自上次备份以来的变化）不同，差异备份的文件会随着时间推移而变大，但恢复时通常只需要一个完全备份和一个最新的差异备份即可，过程相对简单。",
    "source": "文档中「数据备份和恢复」部分的「备份类型」条目",
    "hint": "这种备份方式总是与最近的那个“完整起点”进行比较。"
  },
  {
    "question": "关于系统扩展性，文档中描述的“水平扩展 (Horizontal Scaling)” 的核心思想是什么？",
    "options": [
      "通过升级单个服务器的硬件（如CPU、内存）来提升性能。",
      "通过优化SQL查询和增加索引来提高处理能力。",
      "通过增加更多的计算节点或服务器实例来分散系统负载。",
      "采用微服务架构将应用拆分为独立的服务。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "水平扩展，也称为向外扩展（scale out），其核心是通过增加更多独立的机器或实例来共同分担负载。文档中举例说明了使用负载均衡器将请求分发到多个服务器就是典型的水平扩展。这与垂直扩展（升级单机硬件）形成对比。",
    "source": "文档中「扩展性」部分的「水平扩展与垂直扩展」条目",
    "hint": "想象一下，你是增加更多的人手来一起工作，还是让一个人变得更强壮？水平扩展是前者。"
  },
  {
    "question": "在“数据安全”的实施策略中，应用“最小权限原则”主要是为了实现以下哪个目标？",
    "options": [
      "数据加密，确保数据在泄露后也无法被读取。",
      "访问控制，确保用户只能访问其完成工作所必需的数据。",
      "数据备份，确保数据在丢失后可以被恢复。",
      "安全审计，追踪所有对数据的访问和修改记录。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "文档在“访问控制”条目中明确提到要“使用最小权限原则”。这意味着应该只授予用户、程序或系统执行其任务所必需的最小权限集合。这是一种核心的访问控制策略，旨在限制潜在的恶意或无意操作所造成的损害范围。",
    "source": "文档中「数据安全」部分的「数据安全的实施策略」小节",
    "hint": "这个原则旨在限制权限，而不是保护数据内容本身或记录操作历史。"
  },
  {
    "question": "为了在前端应用中实现高效的数据分页展示，文档在“数据检索”部分推荐联合使用哪两个SQL子句？",
    "options": [
      "GROUP BY 和 HAVING",
      "JOIN 和 WHERE",
      "ORDER BY 和 GROUP BY",
      "LIMIT 和 OFFSET"
    ],
    "correctAnswerIndex": 3,
    "explanation": "文档在“排序和分页”部分明确指出，LIMIT和OFFSET子句用于分页查询。LIMIT用于限制返回结果的数量（每页显示多少条），而OFFSET用于指定从哪一行开始返回（跳过前面的记录），这两个子句的组合是实现数据库分页功能的标准方法，可以提升查询效率和用户体验。",
    "source": "文档中「数据查询和检索」部分的「排序和分页」条目",
    "hint": "想一想，当你要获取“第3页，每页10条”数据时，你需要告诉数据库“跳过多少条”以及“获取多少条”。"
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                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  